EZE is a long way from the city. Taxis are cheap, though (35 pesos)
Don't even think about booking from USA. And if you are quoted a price in dollars, you may safely assume you are paying WAY too much.
In Feb @AEP a kiosk was set up to tout a 4* apartment hotel 50 yds from the obelisk. After some negotiation, price ended up @ 85 pesos/night w/ breakfast, including IVA and taxi ride. Very nice place, takes plastic.
for a look, see
www.broadway-suites.com.ar (rack rate $95 US + 21% IVA, which is what I mean about quotes in dollars)